It's all to protect the baby's growth and development.
Something very important that mothers must do is eat right to avoid infections and to get the right nutrients to the fetus.
"You should avoid soft cheeses because they're loaded with bacteria like listeria," O-B Dr. Samantha Feder said as she advised18 weeks pregnant Rama Diallo on how to eat during the rest of her pregnancy.
It's not just unpasteurized cheeses to avoid. It's also undercooked meat and chicken.
Diallo knows a lot of this.
"Make sure that eggs and meat are welled cooked to avoid the germs and stuff," she said.
Bacteria can lurk in undercooked eggs, so, as Diallo does, make them hardboiled or dry scrambled.
During pregnancy, these are some of the don'ts of eating to protect mother, but most of all to protect the developing baby.
Also don't eat tuna, sword or tile fish more than once a week. They contain high amounts of mercury, which can damage baby's development.
If you start eating healthy when you know you're pregnant, you're already a month late. A woman generally doesn't know she's pregnant until one month later, when she misses the next period.
And that month is when the fetus brain and heart begin to develop. So eat better as you begin to attempt pregnancy.
The dos of pregnancy?
Eat a balanced diet with lots of fruits and vegetables.
Get calcium in low fat products, four servings per day, as baby's bones are growing.
Drink lots of water.
"I drink a lot of water. They say it's very healthy to drink a lot of water during pregnancy," Diallo said.
And watch caffeine, which may slow fetal growth and increase miscarriage risk.
"If you're having one cup of coffee a day, that's ok, but not excessive. One cup of regular tea a day - that would be ok," Teresa Tormey, R.D. at St. Luke's Roosevelt, said.
Avoid alcohol, which can also upset the baby's growth.
Wash salad vegetables very well, perhaps even with dilute soap. Unwashed vegetables can conceal amoebas and other germs that can be very upsetting to a mother's digestive system at any time, but especially during pregnancy.